{"cve":{"cve_id":"CVE-2021-39144","is_kev":true,"kev_date_added":"2023-03-10","kev_vendor_project":"XStream","kev_product":"XStream","kev_vulnerability_name":"XStream Remote Code Execution Vulnerability","kev_short_description":"XStream contains a remote code execution vulnerability that allows an attacker to manipulate the processed input stream and replace or inject objects that result in the execution of a local command on the server. This vulnerability can affect multiple products, including but not limited to VMware Cloud Foundation.","kev_required_action":"Apply updates per vendor instructions.","kev_due_date":"2023-03-31","kev_known_ransomware":false,"kev_notes":"https://www.vmware.com/security/advisories/VMSA-2022-0027.html, https://x-stream.github.io/CVE-2021-39144.html; https://nvd.nist.gov/vuln/detail/CVE-2021-39144","kev_cwes":["CWE-94","CWE-502"],"epss_score":0.98124,"epss_percentile":0.99913,"epss_as_of":"2026-10-15","description":"XStream is a simple library to serialize objects to XML and back again. In affected versions this vulnerability may allow a remote attacker has sufficient rights to execute commands of the host only by manipulating the processed input stream. No user is affected, who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types. XStream 1.4.18 uses no longer a blacklist by default, since it cannot be secured for general purpose.","published_at":"2021-08-23T00:00:00Z","last_modified_at":null,"cvss_v3_score":8.5,"cvss_v3_vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H","cvss_v3_severity":"HIGH","cvss_v4_score":null,"cvss_v4_vector":null,"cvss_v4_severity":null,"ssvc_decision":null,"ssvc_exploitation":"active","ssvc_automatable":false,"ssvc_technical_impact":"total","cwes":["CWE-94","CWE-502"],"nvd_references":["https://github.com/x-stream/xstream/security/advisories/GHSA-j9h8-phrw-h4fh","https://x-stream.github.io/CVE-2021-39144.html","https://lists.debian.org/debian-lts-announce/2021/09/msg00017.html","https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/22KVR6B5IZP3BGQ3HPWIO2FWWCKT3DHP/","https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGXIU3YDPG6OGTDHMBLAFN7BPBERXREB/","https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PVPHZA7VW2RRSDCOIPP2W6O5ND254TU7/","https://www.debian.org/security/2021/dsa-5004","https://www.oracle.com/security-alerts/cpujan2022.html","https://security.netapp.com/advisory/ntap-20210923-0003/","https://www.oracle.com/security-alerts/cpuapr2022.html","https://www.oracle.com/security-alerts/cpujul2022.html","http://packetstormsecurity.com/files/169859/VMware-NSX-Manager-XStream-Unauthenticated-Remote-Code-Execution.html"],"vuln_status":null,"trending_score":null,"is_trending":false,"has_trended":false,"trended_number_one":false,"trending_peak_score":null,"trending_peak_rank":null,"started_trending_at":null,"trended_number_one_at":null,"summary_generated":null,"summary_generated_at":null,"summary_model":null,"created_at":"2026-06-24T00:09:31.350578Z","updated_at":"2026-06-28T23:16:03.418811Z"},"effective_severity":"HIGH","badges":["kev","poc","epss"],"impact_analysis":[],"cvss_v3_decoded":{"version":"3.1","metrics":[{"metric":"AV","name":"Attack Vector","value":"N","value_label":"Network"},{"metric":"AC","name":"Attack Complexity","value":"H","value_label":"High"},{"metric":"PR","name":"Privileges Required","value":"L","value_label":"Low"},{"metric":"UI","name":"User Interaction","value":"N","value_label":"None"},{"metric":"S","name":"Scope","value":"C","value_label":"Changed"},{"metric":"C","name":"Confidentiality","value":"H","value_label":"High"},{"metric":"I","name":"Integrity","value":"H","value_label":"High"},{"metric":"A","name":"Availability","value":"H","value_label":"High"}]},"cvss_v4_decoded":{"version":null,"metrics":[]},"affected":[{"vendor_slug":"x-stream","vendor_name":"x-stream","product_slug":"xstream","product_name":"xstream","version_start":"< 1.4.18","version_start_inclusive":true,"version_end":"< 1.4.18","version_end_inclusive":true,"cpe23_uri":"cve5:x-stream:xstream:< 1.4.18:< 1.4.18"}],"exploit_refs":[{"source":"nuclei","kind":"nuclei","url":"https://github.com/projectdiscovery/nuclei-templates/blob/main/http/vulnerabilities/vmware/vmware-nsx-stream-rce.yaml","title":"VMware NSX Manager XStream Pre-authenticated Remote Code Execution","author":"_0xf4n9x_","disclosed_at":null},{"source":"nuclei","kind":"nuclei","url":"https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-39144.yaml","title":"XStream 1.4.18 - Remote Code Execution","author":"pwnhxl,vicrack","disclosed_at":null}],"news":[],"references":[{"url":"https://github.com/x-stream/xstream/security/advisories/GHSA-j9h8-phrw-h4fh","source_type":"VENDOR_ADVISORY","tags":["advisory"]},{"url":"https://x-stream.github.io/CVE-2021-39144.html","source_type":"MISC","tags":[]},{"url":"https://lists.debian.org/debian-lts-announce/2021/09/msg00017.html","source_type":"MAILING_LIST","tags":["mailing-list"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/22KVR6B5IZP3BGQ3HPWIO2FWWCKT3DHP/","source_type":"MAILING_LIST","tags":["mailing-list"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGXIU3YDPG6OGTDHMBLAFN7BPBERXREB/","source_type":"MAILING_LIST","tags":["mailing-list"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PVPHZA7VW2RRSDCOIPP2W6O5ND254TU7/","source_type":"MAILING_LIST","tags":["mailing-list"]},{"url":"https://www.debian.org/security/2021/dsa-5004","source_type":"VENDOR_ADVISORY","tags":["advisory"]},{"url":"https://www.oracle.com/security-alerts/cpujan2022.html","source_type":"VENDOR_ADVISORY","tags":["advisory"]},{"url":"https://security.netapp.com/advisory/ntap-20210923-0003/","source_type":"MISC","tags":[]},{"url":"https://www.oracle.com/security-alerts/cpuapr2022.html","source_type":"VENDOR_ADVISORY","tags":["advisory"]},{"url":"https://www.oracle.com/security-alerts/cpujul2022.html","source_type":"VENDOR_ADVISORY","tags":["advisory"]},{"url":"http://packetstormsecurity.com/files/169859/VMware-NSX-Manager-XStream-Unauthenticated-Remote-Code-Execution.html","source_type":"EXPLOIT","tags":["exploit"]}],"timeline":[{"type":"published","at":"2021-08-23T00:00:00Z","label":"CVE published","source":null},{"type":"cisa_reported","at":"2023-03-10T00:00:00Z","label":"Added to CISA KEV catalog","source":"kev"},{"type":"poc_available","at":"2026-06-24T00:29:48.638073Z","label":"Public PoC available","source":"nuclei"},{"type":"ssvc_changed","at":"2026-06-24T00:31:45.921816Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"ssvc_changed","at":"2026-06-24T00:31:45.921816Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"ssvc_changed","at":"2026-06-24T00:31:45.921816Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"cvss_changed","at":"2026-06-24T00:31:45.921816Z","label":"CVSS score revised","source":"vulnrichment"},{"type":"cvss_changed","at":"2026-06-24T00:31:45.921816Z","label":"CVSS score revised","source":"vulnrichment"},{"type":"cvss_changed","at":"2026-06-24T00:31:45.921816Z","label":"CVSS score revised","source":"vulnrichment"}]}